JP2554882B2 - Laminated material with excellent aroma retention performance - Google Patents

Description

The present invention relates to a laminated material used for, for example, a container body, a container bottom material, a container lid material, a packaging bag, and the like.

[Conventional technology]

Both surface layers of conventional laminated materials used for packaging bags such as container body parts, container bottom materials, container lid materials, etc. of containers for storing various liquid foods and beverages, tea leaves, spices, etc. It is generally formed into a container or a packaging bag of various shapes by utilizing the thermal adhesion performance of these polyolefin resin layers.

[Problems to be solved by the invention]

By the way, a container or a packaging bag using the above-mentioned conventional laminated material in which both surface layers are composed of a polyolefin resin layer as a container body, a container bottom material, a container lid material, etc., obtains the laminated material. At the time of forming a polyolefin resin layer or forming a container or a packaging bag using the laminated material, the polyolefin resin is thermally decomposed to generate volatile components such as aliphatic hydrocarbons. As a result of migrating into the inner filler contained in the container or the packaging bag, not only has the adverse effect that the inner filler has a change in taste or a bad odor, but the polyolefin resin layer in the laminated material is Since the flavor component in the filler is easily adsorbed or easily permeated, the flavor of the inner filler is likely to change and be impaired.

In order to improve the above-mentioned drawbacks of the polyolefin resin layer, a laminated material is proposed in which a polyethylene terephthalate resin layer having a small amount of volatile substances and good aroma retention is provided as an inner surface layer. However, in a single layer of polyethylene terephthalate resin layer,
The heat sealing strength and impact strength were weak, and it was difficult to put it into practical use.

Further, in JP-A-60-48344, it is described that impact resistance is improved by using a polyester film having a polyolefin resin layer laminated as a heat-sealing layer. The fact is that the adhesive strength between the layer and the polyester film is insufficient, so that a sufficient effect is not obtained.

On the other hand, the present invention, the conventional both surface layers laminated material composed of a polyolefin resin layer, a packaging material comprising a single layer of polyethylene terephthalate resin,
Furthermore, it is intended to eliminate the drawbacks of a laminated material having a polyester film laminated with a polyolefin resin layer as a heat-sealing layer, which is an internal filler in a container or a packaging bag obtained by the laminated material. No change in taste or odor is generated, and the heat generated by the resin layer in the laminated material is obtained by the same molding means as the conventional heat-pressure adhesive molding applied to the laminated material. It is intended to provide a laminated material having a property of being able to be molded into various containers and packaging bags having a sufficient thermal adhesive strength by a molding means utilizing the adhesive ability.

[Means for solving problems]

The laminated material having a property of excellent aroma retention performance of the present invention comprises a base material for a packaging material and a thermoplastic resin layer attached to one surface of the base material for the packaging material. The resin layer is a linear saturated polyester resin layer having a glass transition temperature of 40 ° C. or higher, and ethylene attached to the linear saturated polyester resin layer by an adhesive layer made of an adhesive polyolefin resin. A laminated resin layer comprising a polyolefin resin layer made of α-olefin copolymer, wherein the linear saturated polyester resin layer surface of the laminated resin layer is the outermost layer of the laminated material, It is laminated on the material.

The linear saturated polyester resin layer that constitutes one of the outermost layers of the laminated material of the present invention exhibits excellent aroma retention performance at a temperature lower than the glass transition temperature of the polyester resin that constitutes the polyester resin layer. Therefore, in relation to the fact that the inner filler in the container or the packaging bag is usually placed in an atmosphere of less than 40 ° C., the polyester resin layer has an excellent aroma retaining performance in the atmosphere. Therefore, it is composed of a linear saturated polyester resin having a glass transition temperature of 40 ° C. or higher.

Incidentally, the polyester resin in the linear saturated polyester resin layer constituting the outermost layer on the one side can obtain excellent thermal adhesive strength in the thermal adhesive portion in the container or the packaging bag obtained by the laminated material of the present invention. Therefore, it is preferable to use a resin having a crystallinity as low as possible. The linear saturated polyester resin having a glass transition temperature of 40 ° C. or higher, which constitutes the one outermost layer, is, for example, ethylene glycol, propylene glycol, 1,4-butanediol, 1,4
An alcohol component such as dicyclohexanedimethanol, an aliphatic dicarboxylic acid such as adipic acid or sebacic acid, or a dicarboxylic acid component including an aromatic dicarboxylic acid such as terephthalic acid, isophthalic acid or diphenylcarboxylic acid, specifically, Co-condensation polymers such as ethylene glycol and terephthalic acid, ethylene glycol and isophthalic acid and terephthalic acid, 1,4-dicyclohexanedimethanol and isophthalic acid and terephthalic acid, propylene glycol and isophthalic acid and terephthalic acid can be used. In the case of a cocondensate in which the aliphatic dicarboxylic acid component in the acid component is 10% by weight or more, the saturated polyester resin layer formed by this copolymer is
This aroma-retaining performance tends to deteriorate, which is not preferable.

In the laminated resin layer in the laminated material of the present invention, the adhesive polyolefin resin used as the adhesive layer is, for example, polyethylene, ethylene-α / olefin copolymer, polypropylene, polybutene, polyα-polyethylene such as polyisoptyrene. Olefin, and polydiolein such as polybutadiene and polyisoprene, or copolymers thereof, and ethylene, for example, carboxylic acid, carboxylic acid salt, carboxylic acid anhydride, carboxylic acid ester, carboxylic acid amide or imide, aldehyde, ketone Carbonyl based on etc. Group alone or cyano (-C≡N) group; hydroxy group; ether group; oxirane A copolymer with one or more ethylenically unsaturated monomers having a combination with a ring or the like, and specifically, A. ethylenically unsaturated carboxylic acid: acrylic acid, methacrylic acid, Maleic acid, fumaric acid, crotonic acid, itaconic acid, citraconic acid, 5-norbornene-2,3-dicarboxylic acid, etc. B. Ethylenically unsaturated carboxylic acid anhydride: Maleic anhydride, citraconic acid anhydride, 5-norbornene-2, 3-dicarboxylic acid anhydride, tetrahydrophthalic anhydride, etc. C. Ethylenic unsaturated ester: ethyl acrylate, methyl methacrylate, acrylic acid 2
-Ethylhexyl, mono or diethyl maleate, vinyl acetate, vinyl propionate, propyl γ-hydroxymethacrylate, ethyl β-hydroxyacrylate, glycidyl acrylate, glycidyl methacrylate, β-
N-Ethylaminoethyl acrylate, etc. D. Ethylenically unsaturated amide or imide: Acrylamide, methacrylamide, maleimide, etc. E. Ethylenically unsaturated aldehyde or ketone: Acrolein, methacrolein, vinyl methyl ketone,
An ethylenically unsaturated monomer such as vinyl butyl ketone is used, and among them, an ethylenically unsaturated carboxylic acid or an ethylenically unsaturated carboxylic acid anhydride is particularly preferably used.

The laminated resin layer comprises a linear saturated polyester resin layer having a glass transition temperature of 40 ° C. or higher and a polyolefin resin layer made of ethylene-α / olefin copolymer, and an adhesive made of the adhesive polyolefin resin described above. Although it is attached in a layer, the polyolefin-based resin layer made of the ethylene-α / olefin copolymer attached to the linear saturated polyester resin layer has high impact strength,
Moreover, since it has excellent heat-adhesive performance, the laminated resin layer may have a linear saturated polyester resin layer having a low impact strength or an ethylene-based resin having a high impact strength.
As a result of being covered with a polyolefin resin layer of α / olefin copolymer, the heat-bonded portion obtained by the laminated resin layer exhibits extremely excellent properties in impact strength and heat-bonding strength. Is.

The polyolefin-based resin layer made of the ethylene-α / olefin copolymer is, for example, butene / 1, pentene /
It is formed of an ethylene-α-olefin copolymer using α-olefins such as 1, hexene / 1, methylbutene / 1.

The laminated material of the present invention comprises a linear saturated polyester resin layer having a glass transition temperature of 40 ° C. or higher, an adhesive layer made of an adhesive polyolefin resin, and a polyolefin resin layer made of an ethylene-α / olefin copolymer. The resin layer is affixed to the packaging material base material, and the adhesion between the packaging material base material surface and the polyolefin resin layer in the laminated resin layer is determined by the heat of the polyolefin resin layer. It may be adhered with an adhesive ability, or may be directly adhered to, for example, an Al foil by oxidizing the surface of the polyolefin resin layer, or further may be adhered with an isocyanate adhesive or the like. The base material for the packaging material on which this laminated resin layer is laminated is, for example, when it is a laminated material for a soft packaging container such as a stand pouch, it is generally an Al foil and a biaxially stretched polyester film or a biaxially stretched film. When it is a laminated sheet with polypropylene film, etc., and when it is used as a laminated material for containers such as gable-top type paper containers and brick type paper containers, it is generally composed of Al foil, paper layer, polyolefin resin layer, etc. Laminated sheets are used.

〔Example〕

Hereinafter, the specific constitution of the laminated material having the excellent aroma retaining property of the present invention will be described with reference to illustrated examples.

Example 1 A laminated material having an excellent aroma retaining property of the present invention represented by reference numeral 1 in FIG.
The laminated resin layer indicated by reference numeral 8 is laminated on the base material 4 for packaging material, which is a laminated sheet of the biaxially stretched polyethylene terephthalate film layer 2 and the Al foil 3 having a thickness of 9 μm. The laminated resin layer 8 is composed of a linear saturated polyester resin having a glass transition temperature of 81 ° C. [PET G6763 manufactured by Eastman Kodak Co., Ltd.] having a thickness of 15 μ, and an ethylene-pentene resin layer 5. 1 Copolymer [Mitsui Petrochemical Co., Ltd .: Ultoxex 2021L]
And a polyolefin resin layer 6 having a thickness of 40 μm, which is obtained by adhering it with an adhesive layer 7 having a thickness of 15 μm, which is made of an adhesive polyolefin resin [Novatec AP AX-133E manufactured by Mitsubishi Kasei Co., Ltd.]. In the packaging material base material 4 and the laminated resin layer 8, the Al foil 3 surface of the base material 4 and the polyolefin resin layer 6 surface of the laminated resin layer 8 are separated by the isocyanate adhesive layer 9. It is bonded and laminated.

Comparative Example 1 A base material for packaging material made of a laminated sheet of a biaxially stretched polyethylene terephthalate film having a thickness of 12 μm and an Al foil having a thickness of 9 μm was coated with an isocyanate adhesive on the Al foil surface of the base material. A laminated material [A] for comparison was obtained by forming a 70 μm thick polyolefin resin layer using ethylene-pentene-1 copolymer [Mitsui Petrochemical Co., Ltd .: Ultozex 2021L]. It was

Comparative Example 2 With respect to a packaging material substrate having the same structure as the packaging material substrate 4 used in Example 1, an isocyanate adhesive was used on the Al foil surface of the substrate to obtain a glass transition temperature of 81. ℃ linear saturated polyester resin [Eastman Kodak Co., Ltd .: PETG
6763] to form a 70 μm-thick polyester resin layer to obtain a laminated material [B] for comparison.

Comparative Example 3 With respect to a packaging material substrate having the same configuration as the packaging material substrate 4 used in Example 1, an isocyanate adhesive was used on the Al foil surface of the substrate to obtain a glass transition temperature of 81. ℃ linear saturated polyester resin [Eastman Kodak Co., Ltd .: PETG
6763] and a 15μ thick polyester resin layer, and an adhesive polyolefin resin [Mitsubishi Kasei Co., Ltd .: Novatec
AP AX-133E] and a laminated resin layer with an adhesive layer having a thickness of 55 μm are adhered and laminated so that the polyester resin layer in the laminated resin layer is the outermost layer, and a laminated material [for comparison] C] was obtained.

Comparative Example 4 With respect to a packaging material substrate having the same structure as the packaging material substrate 4 used in Example 1, an isocyanate adhesive was used on the Al foil surface of the substrate to obtain a glass transition temperature of 81 ° C. Linear saturated polyester resin [Eastman Kodak Co., Ltd .: PETG 67
63] and a polyester resin layer having a thickness of 55 μm, and an ethylene-vinyl acetate copolymer [Sumitomo Chemical Co., Ltd .: Evatate D3022, acetic acid content 6%] of a 55 μm thick polyolefin resin layer. A layered material [D] for comparison was obtained by adhering and laminating the layers such that the polyester resin layer in the layered resin layer was the outermost layer.

[Experiment]

Each of the above-mentioned example of the laminated material of the present invention and the laminated material for comparison was used to put orange juice inside.
A 170 mm × 130 mm hermetically sealed packaging bag containing 200 ml.
It was prepared so that the base material surface of the packaging material of each laminated material was the outer surface. The hermetically sealed bag is obtained by heat-sealing the inner peripheral layers of the bag, and is obtained by heat-sealing the four peripheral edges of the laminated material.

When each of the hermetically sealed packaging bags filled with the orange juice is dropped onto the floor from a height of 1.2 m, the impact resistance of the hermetically sealed packaging bags is determined according to the degree of damage to the hermetically sealed packaging bags. By conducting a sensory test on the flavor of the orange juice inside, after investigating and leaving each sealed bag in the atmosphere of 40 ° C for 1 week, it was kept in the orange juice as the filling material. The presence / absence of volatile components present was investigated, and the aroma retention performances of the respective sealed packaging bags were compared.

 The results are shown in Table 1.

[Operation and effect of the invention] Laminated material having excellent aroma retention performance of the present invention, 40
A saturated polyester resin layer composed of a linear saturated polyester resin having a glass transition temperature of ℃ or more,
A laminated resin layer formed by attaching a polyolefin resin layer made of ethylene-α / olefin copolymer and an adhesive layer made of an adhesive polyolefin resin to a base material for various packaging materials. On the other hand, the saturated polyester resin layer in the laminated resin layer is laminated and adhered so as to be the outermost layer, and when it is formed into various containers, packaging bags, etc., it is packaged in the laminated material. The material is used such that the material base material side is the outer peripheral surface layer, that is, the laminated resin layer side of the laminated material is the inner peripheral surface layer.

However, in the laminated material of the present invention having the above-mentioned constitution, the saturated polyester resin layer in the laminated material has an extremely good aroma retaining property at a temperature lower than the glass transition temperature of the resin constituting the saturated polyester resin layer. In addition, the saturated polyester resin layer and the polyolefin-based resin layer formed of the ethylene-α / olefin copolymer are firmly and integrally formed by the adhesive layer formed of the adhesive polyolefin-based resin interposed therebetween. It is affixed to, and has extremely excellent impact resistance in the packaging bag and various containers made of the above laminated material.

The above-mentioned excellent impact resistance provided in the packaging bag or container obtained by using the laminated material of the present invention is the heat seal strength, the impact force applied to the saturated polyester resin layer having weak impact strength is adhesiveness. The adhesive layer made of a polyolefin resin has a high tensile elasticity smoothly, that is, it is transferred to the polyolefin resin receiving layer made of an ethylene-α / olefin copolymer having a high impact resistance, and the high tensile elastic modulus of the layer makes it highly effective. This is because the effect of being relaxed is exhibited by such a shock absorbing force. Incidentally, the polyolefin-based resin layer made of the ethylene-α / olefin copolymer used in the laminated material of the present invention has extremely high impact resistance among the olefin resins and has this property. But,
It provides excellent heat-sealing strength and impact strength to a packaging bag or container obtained using the laminated material of the present invention.

[Brief description of drawings]

The figure shows one of the laminated materials having excellent fragrance retention properties of the present invention.
It is a model cross section which shows an Example product. 1: Laminated material, 4: Base material for packaging material, 5: Saturated polyester resin layer made of linear saturated polyester resin having a glass transition temperature of 40 ° C. or higher, 6: Polyolefin made of ethylene-α / olefin copolymer -Based resin layer, 7: adhesive layer made of adhesive polyolefin resin, 8: laminated resin layer.

Claims (2)

(57) [Claims] 1. A saturated polyester resin layer made of a linear saturated polyester resin having a glass transition temperature of 40 ° C. or higher, and an adhesive layer made of an adhesive polyolefin resin attached to the saturated polyester resin layer. Laminated resin layer consisting of a polyolefin-based resin layer of ethylene-α · olefin copolymer, which is, for the packaging material base material,
A laminated material having a property of excellent aroma retention performance, wherein the saturated polyester resin layer is laminated so as to be an outermost layer. 2. An adhesive layer made of an adhesive polyolefin resin, which is obtained by introducing an ethylenically unsaturated monomer having a carbonyl group into a main chain or a side chain of the polyolefin resin. A laminated material having an excellent aroma retaining property according to claim 1, which is an agent layer.